Development of Prototype Abstraction and Exemplar Memorization

We present a connectionist model of concept learning that integrates prototype and exemplar effects and reconciles apparently conflicting findings on the development of these effects. Using sibling-descendant cascade-correlation networks, we found that prototype effects were more prominent at the beginning of training and decreased with further training. In contrast, exemplar effects steadily increased with learning. Both kinds of effects were also influenced by category structure. Well-differentiated categories encouraged prototype abstraction while poorly structured categories promoted example memorization.